1. Field of the Invention
This invention relates to a communication apparatus and method of monochromatic continually-changing tone pictures and color continually-changing tone pictures. Here, the continually-changing tone picture is defined as a picture having a great variety of modes of tone images continually changing, which differs from monochromatic binary tone pictures and color binary tone pictures that consist of white regions and black regions (or color regions). This invention proposes not an image processing apparatus itself but a communication apparatus excellent in high quality and high speed. Since a color picture can be resolved to three or four primary color pictures having continually-changing tones, each of the resolved primary color pictures can be treated by the same method as the monochromatic continually-changing tone pictures. Therefore, it is feasible to reproduce a color picture by the steps of resolving an original color picture into primary color images, processing the primary color pictures separately, sending the data of the pictures from a sending port, receiving the data of the pictures at a receiving port and synthesizing the primary color images into a unified color picture.
Color resolution and color synthesis are prior technics frequently used for the treatment of color pictures. The gist of this invention exists in the communication processing of monochromatic continually-changing tone pictures. Thus, color pictures are able to be communicated by the same technology as monochromatic continually-changing tone pictures, because the color picture processing is practiced by dealing with individual monochromatic continually-changing tone pictures of primary colors independently. The following explanation mainly gives the processing of monochromatic continually-changing tone pictures.
Recent technical breakthroughs of networks, as the Internet typically represents, are burgeoning. Data are communicated by manifold means of not only conventional telephone lines but various exclusive lines. Further, the wireless communications, for example, pocket telephones, PHSs and so on, are generally expanding day by day. A great amount of data can be easily transmitted between remote places. The Multimedia are going to establish a valid position as a main flow of the information technology. The communication of pictures is the most important subject of the current information technology.
In general, the conditions required for the communication of picture images are as follows:
1. Beautiful and clear picture PA0 2. A small amount of data, that is, a short communication time PA0 1. First drawback is that received pictures are vague and unclear. Here, the interval between individual pixels is called a "sampling interval". If the sampling interval became smaller, it would take longer time to transmit data. Therefore, a picture is usually sampled with a rough interval, which results in an unclear transmitted picture. If an original picture is small and complicated, it is impossible to receive a picture keeping inherent features of an original picture. Transmitted picture loses features inherent in the original picture. Further, since image data are read optically, noises often occur. Particularly, when original pictures are small in size, it is impossible to obtain clear reproduced pictures due to the processes of transmitting and regenerating. When a picture is sent via facsimiles more than twice, a transmitted picture becomes extremely vague due to an increment of noise. Poor and unclear regenerated picture is one of the most serious faults in this method. PA0 2. Second drawback is that a retrieved picture is equal to an original picture in size. Hence, the reduction and enlargement of a retrieved picture are impossible for this method. There exists no freedom of processing. A transmitted picture is able to be enlarged or reduced in size by a copy machine, which brings about a much poorer and unclearer picture that is mostly useless. The degree of freedom of data processing is zero as long as bit map data are processed. PA0 3. Third drawback is that the amount of data is so vast, which is a fatal fault. A large amount of data expenses much time and money in transmitting the data. Therefore, a means of reducing such a large amount of data is desired. PA0 1. Reduction of the labor of transforming continually-changing tone pictures to a certain data form for transmitting them, PA0 2. Feasible enlargement, reduction and transformation of continually-changing tone pictures with high quality, and PA0 3. A small amount of data for transmitting continually-changing tone pictures
High picture quality is an indispensable requirement. This request is getting rigorous due to multiple purposes. It is not practical to take too much time for obtaining high picture quality in fear of the degradation of the quality of picture. A small amount of data, in other words, a short communication time is an essential requirement.
Recently, transmitted images are not only used as they are but also are used for other applications in a great variety of service fields, e.g. digital publications and so on. Hence, the services of picture processing are not restricted within the regeneration of pictures but are expanding to various treatments, for example, the enlargement or the reduction of an object picture in an arbitrary scale, free laying out at an arbitrary position, the printing of the processed pictures and so on without losing the quality of picture. Thus it is ardently desired that transmitted pictures are easy to be processed to various sizes of pictures and so on, and various kinds of picture components are able to be dealt with.
To satisfy these requirements, it is necessary to provide a new communication apparatus using picture formats capable of processing various kinds of picture types and of giving high quality regeneration of pictures, even when the pictures should be transformed in various sizes or into various orientations. In addition, it is essential that the data of pictures are compressed so as to curtail the amount of data and the processing time (including the time of transmitting).
The picture types intended by this invention include, for example, photographs, calligraphic characters, printed characters, illustrations, logomarks and so on. Sizes of pictures are arbitrary, and any color picture with continually-changing tones is available.
Here, the continually-changing tone picture means a picture in which the tone (intensity) of a certain primary color is continually changing spatially. This invention includes color pictures besides monochromatic continually-changing tone pictures. A color picture is able to be resolved into several primary color pictures having continually-changing tones, and be reduced to a monochromatic continually-changing tone picture of every color. For example, when a color picture is resolved into four primary colors, it has four monochromatic continually-changing tone pictures with respect to each primary color, so that individual treatments are practiced on every primary color.
This invention aims at processing the pictures as an aggregation of a plurality of primary color pictures in which tones (intensities) widely vary in succession.
Here, a continually-changing tone picture is used as an antonym of a simple two-value picture (binary tone picture) that is briefly constructed with the regions of black and the extra regions of white. Thus, the objects of the present invention include not only tone-changing monochromatic pictures but also tone-changing color pictures. According to the definition of the word of "continually-changing tone picture" alone, it seems to exclude binary tone pictures. This invention is, however, also capable of processing both binary tone pictures and continually-changing tone pictures due to its affluent generality. Thus, this invention is excellent in versatility.
This invention is likely to say "Communication apparatus and method of pictures", but is titled as "Communication apparatus and method of color pictures and continually-changing tone pictures", because this invention is capable of processing continually-changing tone pictures that are extremely difficult in processing in comparison with binary pictures. And further, the word of "color" is inserted to the title, because this invention is defined as the technology for not only monochromatic two-value pictures but also color continually-changing tone pictures. Hence, this title shows that this invention enables to process multiform pictures.
This invention enables to input an original continually-changing tone picture by a picture reading apparatus or a picture inputting apparatus, obtain multivalued data from the inputted picture, eliminate noises, reduce the amount of data without losing inherent features of the continually-changing tone picture, compress the data, transmit the compressed data via telephone lines, exclusive lines, or electric waves, and retrieve the original continually-changing tone picture from the transmitted data.
In particular, this invention implements the steps of automatically transforming an original picture with continually-changing tones to digital data, transmitting these digital data to remote places via various media, retrieving the original picture from the digital data in an arbitrary scale, and utilizing the retrieved picture via a printing apparatus or a computer.
In the case of a color picture, this invention dissolves preparatively a read-in original color picture into four or three primary color monochromatic pictures, processes the primary color monochromatic pictures independently to digital data, eliminates noises from the digital data, reduces the amount of data, compresses the data, transmits these digital data to remote places via various media, regenerates each primary color picture from the compressed data without losing inherent features, and synthesizes the primary color pictures into a single continually-changing tone color picture.
2. Description of the Prior Art
This application claims the priority with respect to Japanese Patent Application No.230451/1997 filed on Aug. 11, 1997 which is incorporated herein by reference.
Conventional communication apparatuses are able to transmit coded-data such as characters and so on without the degradation of picture quality as digital data because of a small amount of data, but are fully unable to transmit a continually-changing tone picture that has never been coded without reducing the quality of picture in a short time because of a great amount of information. Any practical technology, which is able to transmit pictures with an extremely large amount of information in a short time without degrading the quality of the pictures, has never been contrived yet.
Three types of current data compressing methods will be disclosed instead of communication technique. Here, we emphasize the fact that there yet exists no practical communication technology for transmitting the compressed data of a continually-changing tone picture via telephone lines or exclusive lines.
Three current methods of compressing data are (A) BIT MAP DATA METHOD, (B) DISCRETE COSINE TRANSFORMATION METHOD (DCT METHOD) and (C) FUNCTION-APPROXIMATION METHOD. (A) is a method of transmitting data without compressing the data. (B) and (C) are methods of compressing data but are not yet put into practical use for communication.
These three methods will be explained in detail as follows:
(A) Bit Map Data Method
This is a method of transmitting bare continually-changing tone values of all pixels of a picture input from an image reading apparatus, for example, a scanner without data processing. This method seems to be a sole method realizing the transmission of images at present. Here, the bit map means a set of pixels having continually-changing tone values of a picture. This method transmits the tone values of all the pixels without compressing and processing them.
For example, facsimiles (both binary and multi-valued facsimiles) widely prevailing nowadays adopt this bit map data method. Here, data are changed from analog signals to digital signals, and the digital signal data are encoded, for example, by the Huffman encoding. Encoding process is directed to protect the secret of the data, being accompanied by some decrease of data. Data of pictures themselves are not compressed. Therefore, it is safely said that the bit map method directly transmits numerous data of a picture as they are. Any sort of picture types is possible to be sent because of the direct transmission of data. This method is an extremely simple one, but has serious drawbacks, which will be pointed out in the next stage.
Fault 1 might be conquered to some degree by shortening sampling intervals, and whereby a transmitted picture would keep more features inherent in an original picture. If so, the amount of data would be increased, which results in expending far more time and money for transmitting the data.
Technologies of compressing data for transmission have been devised by making use of encoding systems, e.g. Run length coding Method, Modified Huffman Coding Method, and so on in order to shorten the time of transmitting data. Since these methods encode digital data directly, the compression of data is limited to a small extent. Such methods directly encode digital data, disregarding all features inherent in original pictures. To shorten the time of transmitting data, the sampling intervals of facsimile are still too wide, and whereby the quality of received pictures is still bad. A retrieved picture ends up with losing delicate and close features faithful for the original picture.
As explained hitherto, although the bit map data method is only a method that has already been realized in the transmission of data of a picture, the quality of transmitted pictures is bad. It is infeasible for this method to retrieve pictures to a satisfactory level of the quality of picture.
(B) Discrete Cosine Transformation Method (DCT Method)
This is a method of compressing the data of pictures and obtaining coefficients of the compressed data by using discrete cosine functions. The data compression by the discrete cosine transformation method is made use of by the standard compressing means of stationary pictures, e.g. JPEG and so on. This method is utilized only for the data compression but has never been put into practice for the communication of images. Since data are reduced by this compressing method, the data would easily be transmitted. Further, this method may be effective in a picture having smooth continually-changing tones but is incompetent for a picture in which the tones change drastically. In the concrete, a picture including discontinuing tones is suffering from block distortion and edge degeneration. The incompetence for quick-changing tones induces a fatal drawback of degrading the quality of a picture composed of various types of images, for example, photographs, calligraphic characters, printed characters, illustrations, logomarks and so on. Furthermore, the DCT method still lowers the quality of a picture accompanying enlargement or reduction. Therefore, this DCT method is unsuitable for such data treatments as enlargement, reduction, transformation and so on.
(C) Function-Approximation Method
This is a method of approximating a picture by expressing picture image components as combinations of basic functions and reducing the picture to the coefficients of functions. Approximation methods based on this idea have been disclosed in prior documents, that is, Japanese Patent Laid Open No.6-83952, Japanese Patent Laid Open No. 6-96199, Japanese Patent Laid Open No.6-348837 and Japanese Patent Laid Open No.7-85268. These methods are fully incompetent to continually-changing tone pictures but are effective to binary tone pictures of characters, illustrations and so on that have only white pixels and black pixels. Outlines of a binary tone picture are approximated by straight lines, circles, arcs and free curves in the order, and the outline parameters are stored in a memory. Hence, the outlines are expressed by straight lines, arcs, circles and free curves. This method is capable of compressing data by expressing a binary tone picture with simple figure elements.
This is, however, the method of approximating outlines of a binary tone picture consisting of only white pixels and black pixels. Therefore, this method is inadequate for continually-changing tone pictures that have no outlines. This method is absolutely useless for continually-changing tone pictures such as photographs in which peripheral lines cannot be clearly defined. Further, these prior methods have not been practiced in use even for transmission of binary tone pictures.
Any technology capable of transmitting continually-changing tone pictures by the function approximation method has never been realized yet.
It is no exaggeration to say that any transmitting technology has never succeeded in reducing the data amount of a continually-changing tone picture, transmitting the picture without losing features inherent in an original picture, retrieving a transmitted picture with maintaining inherent features and processing the transmitted picture into various forms, e.g. enlargement, reduction, deformation and so on. In the conventional bit map data method, the inherent features of an original picture are blurred and the quality of picture is degraded. A shorter sampling interval between pixels would be effective to transmit data more faithful to the original picture, which would incur in a great amount of data and a lot of processing time. Therefore, it is impossible to shorten the sampling interval so much. As a result, this bit map data method cannot avoid the degradation of quality of picture caused by transmitting.
DCT method is capable of compressing data, but the quality of picture is very bad when various image types are intermingled in a picture. It is infeasible to enlarge or reduce an object picture in size without degrading the quality of the picture. DCT method has not yet attained the use in practice as a picture communication technology.
As mentioned above, there exists no effective method for processing continually-changing tone pictures by using the function-approximation method, as satisfying the above described requirements.
It is convinced that there exists no technology for transmitting fine continually-changing tone pictures with enjoying high quality in a short time together with another processing, for example, enlargement, reduction and so on. The recent development of communication systems ardently desires the realization of the transmission of continually-changing tone pictures more and more.
Conventional image transmitting technologies can not transmit pictures that requires extremely high accuracy like a block copy of printing. There is no means for sending such a picture requiring extremely high accuracy to other places except enclosing it in an envelope and sending the envelope by mail. It takes a few days to send a picture. It would be extremely convenient, if a new technology can send a picture endowed with high accuracy in an instant, maintaining inherent features faithful in an original picture. If so, we are released from the anxiety about the delay of transport.